Electropneumatic or electrohydraulic cutoff, flanging and re-forming of tubing

ABSTRACT

Disclosed herein is apparatus and method for the electropneumatic or electrohydraulic severing, flanging, reforming and the like of members such as, for examples, container bodies and the like. The force generated for performing these operations is created through the application of electrical energy to a pair of electrodes positioned within a chamber to provide an electrical discharge within such chamber. The electrical discharge creates a plasma bubble between the electrodes and such bubble continues to grow as continued power is supplied to the electrodes. The force so created drives the wall of the member or workpiece against an adjacent die to perform the desired operation or operations.

United States Patent [1 1 Roth [4 1 Jan. 22, 1974 [75] Inventor: DonaldJ. Roth, Chicago Heights,

[73] Assignee: Continental Can Company, Inc.,

New York, NY.

[22] Filed: Aug. 31, 1970 [21] Appl. No.: 68,505

Related U.S. Application Data [63] Continuation of Ser. No. 441,017,March 19, 1965,

abandoned.

[52] U.S. C1. 72/55 [51] Int. Cl B21d 28/18 [58] Field of Search 72/56,55; 29/421 E; 113/120 R, 120 AA [56] References Cited UNlTED STATESPATENTS 2,298,132 10/1942 Johnson 29/421 2,966,872 1/1961 Schmocker....72/55 3,288,006 11/1966 Erlandson 72/55 3,222,902 12/1965 Brejcha et a172/56 3,163,141 12/1964 Wesley et a1. 72/56 3,090,113 5/1963 Karpovich29/421 3,206,845 /1965 Crump 29/421 3,252,312 5/1966 Maier 72/563,286,497 11/1966 Cary 113/120 OTHER PUBLICATIONS High-Energy RateForming; Product Engineering; October 15, 1962; by R. W. Carson; pages86-100.

Primary ExaminerRichard J. Herbst Attorney, Agent, or FirmDi11er, Brown,Ramik & Holt [5 7] ABSTRACT Disclosed herein is apparatus and method forthe electropneumatic or electrohydraulic severing, flanging, re-formingand the like of members such as, for examples, container bodies and thelike. The force generated for performing these operations is createdthrough the application of electrical energy to a pair of electrodespositioned within a chamber to provide an electrical discharge withinsuch chamber. The electrical discharge creates a plasma bubble betweenthe electrodes and such bubble continues to grow as continued power issupplied to the electrodes. The force so created drives the wall of themember or workpiece against an adjacent die to perform the desiredoperation or operations.

10 Claims, 11 Drawing Figures PATENTED I974 3,786, 682

SHEET 3 [IF 3 ELECTROPNEUMATIC OR ELECTROHYDRAULIC' CUTOFF, FLANGING ANDRE-FORMING OF TUBING This application is a continuation of Ser. No.441,017, filed Mar. 19, 1965, now abandoned.

This invention relates to severing, flanging, and reforming'means andmore specifically to apparatus and methods for performing theseoperations by the employment of an arc discharge in an electropneumaticor electrohydraulic medium.

Heretofore, in operations relating to the fabrication of containerspossessing thin walls, the initial step in the fabrication of thecontainer is to sever a portion from stock material. This portion, knownas a blank, is then advanced to means which form the blank in thedesired configuration. The operations of cutting or severing, flanging,reshaping and/or re-forming were accomplished at relatively slow speedsand each operation was performed individually. If the fabrication ofcontainers, whether they be of metal, plastic, paper or any combinationof these materials, is to be truly successful, then the operation mustbe performed at high speed, with economies of operation, and thefabrication must be easily controlled.

The present invention contemplates that rather than severing a blankfrom a roll of stock material and then proceeding with the subsequentfabrication operations, the stock material would ,be formed in thedesired configuration directly and then severed after the configurationof the container has been accomplished. In addition, it is envisioned bythe practice of the present invention that a pluraltiy of operationsperformed in the heretofore manner, would be accomplished in a singleoperation.

At the present time, there is no known truly successful manner forsevering a cylindrical container after the container has been formedinto a cylindrical body. A die may be employed in a usual manner tosever the container; however, the. usual severing operation results in adistortion of the container to such a degree that re-forming is eithermandatory or is impossible.

In addition to the severing capabilities of the invention, the flangingof the container body would be accomplished at the same time as thesevering operation. Accordingly, it will be intuitively clear that agreat savings in time and material will be effected by combining theprevious steps of severing and flanging into a single operation.

The principles of the invention may also be applied to the operation ofre-forming or reshaping a container body. It will be understood thatthroughout the specification reshaping and re-forming are synonymous andwill be used interchangeably. The re-forming operation could beperformed before or after the severing and flanging operation aspreviously outlined. If it is desired, the re-forming operation could beperformed by a continuous operation without the necessity of halting thecontainers while traveling through the fabrication process.

Accordingly, it is the principal object of the present invention toimprove container severing techniques.

It is a further object of the present invention to improve containersevering techniques employing the force created by the discharge of aspark across a pair of electrodes.

It is a further object of the present invention to improve containerre-forming or reshaping techniques by the force created through thedischarge of a spark across a pair of electrodes.

It is a further object of the present invention to provide a systemcapable of simultaneously performing a severing and flanging operationon container bodies.

It is a still further object of the present invention to provide a meansfor performing operations on container bodies by causing a sparkdischarge in a fluid medium to displace the body according to apredetermined configuration.

Although a number of operations are shown and described which may beperformed on container bodies, the principle of the invention relatesto, in one embodiment, positioning a length of cylindrically formedmaterial within a restraining means and severing a portion of thematerial, which severing takes place radially and completely about theperiphery of the container. The container edge may also be flangedsimultaneously with the severing operation. The container body ispositioned within a circular die and supported about the insideperiphery of the die is a cutting or severing knife. Within the die, achamber is formed which houses a pair of electrodes. The chamber mayhouse any one of a number of fluids, such as air, water or oil of highdielectric constant, etc. When a power supply capable of causing adischarge to take place between the electrodes is applied to connectingleads, the force created by the discharge is transmitted through thefluid to the inside wall of the container. At the point where thecutting knife meets the container, a severing operation will result. Thecutting knife is beveled which permits the rapidly moving severedcontainer edge to continue on into the beveled area (a void between theside of the severing knife and the die) to then result in a flangingoperation. Due to the elasticity of the material, a certain amount offlanging may take place just prior to the complete severing of thecylindrical wall of the container. The energies which force the wall ofthe container against the severing-flanging die are created by thedischarging of the high current spark across the spark gap. A plasmabubble is formed in the spark gap and continues to grow as continuedpower is supplied to the electrodes. This expansion, in one embodiment,forces the elastomeric material out very rapidly against the tubing,causing the desired operation on the tubing. This force occurs withinmicroseconds so that a very rapid severing and flanging rate may bemaintained.

in addition to the severing and flanging operation, a re-formingoperation may be performed. 1n the reforming operation, the severingknife die is replaced with a re-forming die in which the spark dischargecauses the container wall to be violently forced against the re-formingdie to result in a forming or re-forming operation.

Various modifications are anticipated, one of which would be thepositioning of the severing knife within the container, with thesevering operation to be accomplished by driving the container wallinwardly. In addition, various combinations of severing, re-forming, orflanging may be accomplished by positioning the elements of theinvention in the desired manner.

The invention, both as to its organization and method of operation,together with further objects and advantages thereof, will best beunderstood by reference to the following specification taken inconjunction with the accompanying drawings in which:

FIG. I is a cross-sectional side elevation view showing a cylindricalmember in position for severing and flanging;

FIG. 2 is a sectional view taken on the line 2-2 of FIG. 1;

FIG. 3 is a fragmentary view of a modification of the form of theinvention illustrated in the FIG. 1;

FIG. 4 is a cross-sectional view showing one form of the re-former and acylindrical body in position for reforming;

FIG. 5 is a cross-sectional side elevation view similar to the view ofthe FIG. 1 and illustrating a modified form of the invention wherein theelectrodes are disposed about the container body;

FIG. 6 is a sectional view taken on the line 6-6 of FIG. 5;

FIG. 7 is a sectional side elevation view similar to the view of theFIG. 1 and illustrating a modified form of the invention.

FIG. 8 is a fragmentary view of a modified form of the invention shownin the FIG. 1;

FIG. 9 is a sectional view similar to the view of the FIG. 4 andillustrating a modified form of the container re-former or reshaper anda container body'in position to be re-formed or reshaped;

FIG. 10 is a sectional view similar to the view of the FIG. 9 butillustrating a type of embossing die wherein undulations are formed inthe container wall to result in a reshaping or re-forming of the tube orcontainer body; and

FIG. ll is a sectional view taken on the line ll-ll of the FIG. 10.

It may be noted at this point, that the apparatus shown in the FIGS. 1through 6 is best suited for performing operations with the sparkdischarge being in an atmosphere of air or other gas. These embodimentsmay be termed electropneumatic. The apparatus shown in the FIGS. 7through 11 are best suited for operations wherein the chamber enclosingthe spark discharge area contains a liquid. These embodiments may betermed electrohydraulic. However, it will be understood that either agas or liquid may be employed in any of the apparatus illustrated in thefigures.

With reference to the FIGS. 1 and 2, a cylindrical die surrounds acylindrical tube or container body 22. The die 20 is split at 24 and 26to facilitate the removal of a severed and flanged container body byseparating the die 20, which separation means are not shown.

Supported within the die 20 and directed inwardly is a severing knife 28having its severing surface substantially perpendicular to the containerbody 22. The container body 22 fills substantially all the area withinthe inside of the die 20 and may or may not lightly engage the die 20 inthe absence ofa severing operation. It will be noted that the severingsurface or point of the severing knife 28 extends to a pointsubstantially in line with the inside periphery of the die 20. Formednext to the severing knife 28 and on the die 20 is a flanging radius 30which controls the shape of the flange formed on the edge of thecontainer body 22 when the container body 22 is driven against thesevering knife 28 and severed. By varying the flanging radius 30, on thedie 20, a great variety of shapes and sizes of flanges may be derived.By reducing the flanging radius 30 to substantially zero, then little orat best a very small radius would be formed on the container body 22. Itwill be intuitively clear that a certain area must be provided next tothe severing knife 28 to-permit the knife 28 to completely penetrate thewall of the container body 22, if such is desired.

In the FIGS. 1 and 2, a horn extension 32, of slightly lesser diameterthan the container body 22, supports the means within the die 20 tocause the severing and flanging operation. A gas chamber 34 is formedbetween a sealing plate 36, which is rigidly connected to the hornextension 32 and a second sealing plate 38 which is held in place by aplurality of spacers 40. Thus, the chamber 34 is formed in the areabetween the sealing plates 36 and 38. The chamber 34 is substantiallysealed between the sealing plates 36 and 38 and the container body 22 bya pair of low friction seals (such as the familiar O-ring) 42 and 44,respectively. The horn extension 32 would be movable and would normallyplace the chamber 34 in a position within the area toward which thesevering knife 28 is directed.

Supported by any suitable means, not shown, are a pair of electrodes 46and 48 which are coupled to a power supply, not shown, by the conductors50 and 52, respectively. The force which does the mechanical work ofsevering and/or flanging a container body 22 is created by discharging ahigh power spark across the electrodes 46 and 48. A plasma bubble isfomred in the spark gap between the electrodes 46 and 48 and continuesto grow as additional power is applied to the electrodes by the powersupply, not shown. The spark discharge causes heating and vaporizationof some of the fluid and expansion of this vapor along with gasesentrapped within the fluid. The bubble thus generated displaces thefluid which in turn provides the force for subsequent operation. Thus, acylindrical body such as a container body 22 would be thrown outwardlyand against the severing knife 28 and into and about the flanging radius30. The die 20 would then be opened by any conventional means, and thesevered portion of the cylindrical body 22 would be removed and theremaining portion of the cylindrical body 22 would be advanced to thepoint where another severing and/or flanging operation is desired.

Spark discharges between a pair of electrodes, such as the electrodes 46and 48 in the FIG. 1, are well known in the art and do not need to beexplained in detail with reference to the invention.

The FIG. 3 shows a modification of the chamber sealing means of theFIG. 1. As the FIG. I employs a pair of O-rings 42 and 44, the apparatusof the FIG. 3 employs inflatable members. The chamber 34 is formed bythe sealing plates 54 and 56. About their peripheries and engaging theinner circumference of a container body 22 are the inflatable tubes ormembers 58 and 60, positioned respectively upon the sealing plates 54and 56. The sealing plate 54 is connected to the horn extension 32 (in amanner similar to that shown in the FIG. 1) and the second sealing plate56 is supported by a spacer 62 which is rigidly coupled to the sealingplate 54. Communicating with and within the sealing plate 54, is apassage 64 which connects with a source of pressure within a tube suchas the air supply tube 66. The tube 60 communicates with the air supplytube 66 through a passage 68. The electrodes 46 and 48 are substantiallyidentical to those shown in the FIG. I.

In the embodiment of the FIG. 3, the tubes 58 and 60 would be deflatedduring positioning of a container body or cylindrical tube 22 and uponthe container body 22 reaching the point at which it is desired to severand/or flange'the body 22, a source of pressure would be applied to theair supply tube 66 which would inflate the tubes 58 and 60 and engagethe inside circumference of the container body 22 to effect a sealformed within the chamber area 34 defined by the sealing plates 54 and56 and the inner circumference of the container body 22. When anappropriate source of potential is applied to cause a discharge betweenthe electrodes 46 and 48, the container body 22 would be abruptly drivenagainst the severing knife 28 and the flanging radius 30 to result in acomplete severing and flanging of the container body 22.

During certain operations, the container body or cylindrical tube 22,whether metal, plastic, paper or any combination of these materials, maybecome distorted and require a re-forming or re-shaping of thecylindrical body. Accordingly, such a means is provided by theembodiment of the FIG. 4 wherein like elements are designated in amanner similar to those of the FIG. 1. The sealing plates 36 and 38 arepositioned a greater distance apart than those of the FIG. I as shown bythe designation 40. The sealing members 42 and 44 are positionedentirely about the sealing plates 36 and 38, respectively, and form achamber 34' within the area enclosed by the sealing plates 36 and 38,the seals 42 and 44, and the inside circumference of a container body orcylindrical tube 22.

As shown in the FIG. 4, a re-forming or re-shaping die 70, ofcylindrical shape, completely surrounds the container body 22 and inproximity thereto. When a discharge is effected between the electrodes46 and 48, the gas within the chamber 34' would be heated and theconfined air, would produce a very high gas pressure due to its thermalexpansion. This energy, would force the container body 22 against there-forming die 70 to result in a re-shaping or re-forming of the body.

In the FIG. 4, it will be noted that the re-forming die 70 is positionedexternally to the member to be shaped. In the embodiment shown in theFIGS. 5 and 6, the reforming die is positioned within the body and thedischarge'is caused between pairs of electrodes withina chamber formedabout the body,

The apparatus of the FIGS. S and 6, will perform a re-forming orre-shaping operation by directing the reshaping energy inwardly towardthe center of the container body 22. A U-shaped channel 72 iscylindrical with the open portion of the U" directed inwardly towardsimilar configurations of the channel. A reforming die 74 is positionedwithin the cylindrical U- shaped channel 72 but is of slightly lesserdiameter than the diameter of the area within the body 72. A containerbody 22 is positioned between the outer extremities of the reforming die74 and the inner circumference of the U-shaped channel 72. A pair ofsealing members 42 and 44 are positioned within the notches of theprojecting members of the U-shaped channel 72 and are in engagement withthe outer circumference of the container body 22. The seals or O-rings42 and 44 are of a low friction material to permit sliding engagementbetween the container body 22 and the seals 42 and 44.

A plurality of pairs of electrodes 46 and 48, having electrical leads 50and 52 coupled, respectively, thereto, are positioned about the chamberformed within the U-shaped member 72 and in the particular embodimentshown and described, four such pairs of electrodes are shown; however;it will be understood that any number of pairs of electrodes may beprovided according to the requirements of the operation to be performed.

Thus, with a container body or cylindrical tube 22 in the position shownin the FIG. 5, a substantially sealed and closed chamber is formedwithin the U-shaped member 72 and the container body 22. Upon theapplication of a suitable power source to the conductors 50 and 52, adischarge will be caused to occur between the electrodes 46 and 48 andits resulting thermal expansion of the gases within the chamber, willforce the walls of the container body 22 inwardly against the reformingdie 74 to result in a re-forming or reshaping operation.

Whereas the FIGS. 1 through 6 disclose embodiments of the inventionwherein the chamber would contain an atmosphere such as air, theembodiments shown in the FIGS. 7 through 11 are known aselectrohydraulic forming means and would employ a fluid within thechamber such as water, and oil of high electric constant, or othersuitable material. The fluid is contained within the chamber by anelastomeric material to be hereinafter described.

One form of this embodiment is shown in the FIG. 7. The die 20 and thesevering knife 28 surround the container body 22 as in the FIG. 1. Thehorn extension 32 supports a first sealing plate 76 to the left of thesevering knife 28 and a second sealing plate 78 to the right of thesevering knife 28. It is not necessary that the knife 28 be centeredbetween the sealing plates 76 and 78 but may be anywhere in line with achamber 82 and about an elastomeric material 80. The elastomericmaterial 80 of circular configuration is hollow and joins the sealingplates 76 and 78. The outside circumference of the elastomeric material80 may or may not loosely engage the container body 22 and may besecured to the sealing plates 76 and 78 in any suitable manner. A fluidchamber 82 is now formed within the confines of the elastomeric material80. A pair of electrodes 46 and 48 are positioned within the fluidchamber 82 and have connecting electrical leads 50 and 52 coupledrespectively, thereto. The force which performs 'the mechanical work tocause severing and/or flanging of a container body 22 in the FIG. 7,iscreated by discharging a high voltage spark across the electrodes 46and 48. A plasma body or bubble is formed in the spark gap between theelectrodes and continues to grow as continued power is applied to theelectrodes 46 and 48. This forces the elastomeric material 80 out veryrapidly against the body or tubing 22, causing the tubing 22 to expandagainst the die to result in a severing and flanging operation.

In the FIG. 8, a re-forming apparatus is shown which employs a fluidchamber 82 which completely surrounds the container body 22 to bere-formed. Whereas the embodiment in the FIG. 5 discloses theelectropneumatic arrangement, the electrohydraulic arrangement is shownin the FIG. 8. A U-shaped channel 72 is of circular configuration andcompletely surrounds the container body 22 and the re-forming die 74.The elastomeric material 80 provides a seal to contain the fluid withinthe chamber 82'. Upon the application of a suitable voltage to theconductors 50 and 52, the resulting discharge between electrodes 46 and48 will force the elastomeric material 80 against the container body 22to result in a re-forming or reshaping operation.

In the FIG. 9, a re-forming or reshaping apparatus is shown whichdirects its forces outwardly, unlike the embodiment of the FIG. 8 whichdirects its reshaping forces inwardly. The sealing plates 76 and 78 arepositioned a greater distance apart than that in the FIG. 7 so thatreshaping may take place over a greater distance, which expanse is notrequired in a severing operation to which the apparatus of the FIG. 7 isdirected. The elastomeric material 80 joins the sealing plates 76 and 78and may be in intimate contact, loose contact or not in contact at allwith the container body 22. Arranged circumferentially about thecohntainer body 22 is a re-forming dic 70, similar to that shown in theFIG. 4. Upon the application of a suitable voltage, the spark dischargebetween the electrodes 46 and 48 will cause the-material 80 to be drivenoutwardly and force the container body 22 against the inner wall of thereforming die 70, to result in a reshaping of the container body 22.

The elastomeric material 80 may be of any suitable construction such asrubber, plastic, etc., and need be deformable by-pressure within thechambers 82 and 82'. It is sufficiently resilient and yielding totransmit any pressure waves caused by the spark discharge between theelectrodes 46 and 48 to the container body 22. The amplitude andduration of the electrical supply coupled to the conductors 50 and 52may be controlled by any suitable control means. In addition, capacitorsmay be utilized to assure the correct energy charge applied to theelectrodes 46 and 48. The control then, will include suitable means forapplying the appropriate voltage to the capacitor, suitable impedancemeans in the capacitor and spark gap circuit to vary the time constantof the circuit, and thereby control the discharge rate. In addition,suitable means would be provided to control the time intervals betweensuccessive energizations of the electrodes.

The FIGS. I and I1 illustrate reshaping or reforming means and aresimilar to the illustration of the FIG. 9 except that instead of asmooth die 70, the die 70' of the FIG. 10 has formed about its innerwall a plurality of undulations 84. When a spark discharge appearsacross the spark gap formed by the electrodes 46 and 48, the resultingoutward movement of the elastomeric material 80 drives the containerbody 22 into the undulations 84 which result in rings or beads about thecircumference of the container 22, which beads provide added strengthand esthetic appeal. It will be understood that any number ofundulations 84 may be provided and that the undulations 84 may be of anysuitable geometric shape in which it is possible to form the containerwall 22 without a severing or parting of the material. Further, it willbe readily understood that reshaping may take many different forms andthat the dies 70 may be conical, square, triangular, etc., or anycombination of these geometric figures. As the container material 22 ortube is advanced through or about the dies so formed, excitation of theelectrical energy will cause the elastomeric membrane 80 to drive thecontainer body 22 into engagement with the conforming die.

Thus, there has been described a means for severing, flanging, reshapingor re-forming cylindrical containers by the use of the electrical energycreated through a spark discharge across a pair of electrodes. In afirst embodiment, either of the operations may be performed within achamber containing a gas such as air. In other embodiments, the chambermay, as well as a gas, contain water or an oil which will transfer theforce resulting from the electrical discharge between the electrodes 46and 48 to cause the desired operation to the container wall. It will beunderstood that severing and/or flanging and/or re-forming may beperformed either simultaneously, separately, or in any usefulcombination, as desired. For example, a re-forming operation may precedeor follow a severing operation and severing and flanging may beperformed substantially simultaneously. It may be an advantage to do allthe operations simultaneously.

Thus, the present invention may be embodied in other specific formswithout departing from the spirit and the essential characteristics ofthe invention. The present embodiment is, therefore, to be considered inall respects as illustrative and the scope of the invention beingindicated by the appended claims rather than the foregoing dsscription,and all changes which come within the meaning and range of theequivalency of the claims are, therefore, intended to be embracedtherein.

I claim:

I. Tubular body forming means comprising an annular die having acircular portion removed about its inner periphery, flanging radiusesformed at the junction of the removed portion and the inner surface ofsaid die, a severing knife positioned within the removed portion of saiddie, means defining a chamber within the die but permitting thepositioning of a body between the severing knife and the chamber means,and means for developing an electrical discharge within said chamber toproduce severing and flanging of a body at a predetermined point bycausing the portion of a body juxtaposed the severing knife to beadvanced toward the severing knife and .against the flanging radius.

2. Tubular body forming means comprising annular severing means, a firstsealing plate, a second sealing plate spaced apart from and supported bysaid first sealing plate, the area between said first and said sec- 0ndsealing plates defining a chamber, means for supporting said sealingplates within the severing means but permitting the positioning of abody between the severing means and the chamber defined by said sealingplates, and means for developing an electrical discharge within saidchamber to produce a severing of a body at a predetermined point bycausing the portion of a body juxtaposed the severing means to beadvanced toward the severing means.

3. The combination as defined in claim 2 including resilient meanspositioned upon each of said sealing plates to effect a seal between itsrespective sealing plate and a body to be formed.

4. The combination as defined in claim 3 wherein said resilient meansare O-rings of low frictional material.

5. A cylindrical body forming means comprising an expandable annulardie, a groove formed about the inside of said die, flanging radiusesformed at the junction of the groove and the inside of said die,severing means positioned within said groove and directed inwardly, afirst circular plate member, a second circular plate member positionedapart from and supported by said first plate member, the area betweensaid first and said second plate members defining a chamber having agaseous atmosphere, a horn extension for supporting the circular platemembers within the die but permitting the positioning of a body betweenthe severing means and the plate members, resilient means positionedupon each of said plate members to effect a seal of the chamber to thebody to be formed, and a pair of electrodes positioned within thechamber and between said first and said second plate members fordeveloping an electrical discharge within said chamber and causing anexpansion of the gaseous atmosphere to produce severing and flanging ofa body at a predetermined point of the body by driving the portion of abody juxtaposed the severing means and flanging radius to be advancedtoward the severing means and the flanging radius.

6. Cylindrical body forming means comprising an expandable annular die,a severing knife positioned within said die and directed inwardly, ahorn extension, a pair of circular plates supported by said hornextension and defining a chamber within the die but permitting thepositioning of a body between the severing knife and the circularplates, inflatable means positioned about the periphery of each of saidcircular means to effect a seal between its respective circular meansand the body to be formed, and means for developing an electricaldischarge within said chamber between said circular plates to produce asevering of a body at a predetermined point by causing the portion of abody juxtaposed the severing knife to be advanced toward the severingknife.

7. The combination as defined in claim 6 including a passagewaycommunicating with each of said resilient means positioned upon saidcircular plates for expanding said resilient means.

8. Cylindrical body forming means comprising annular severing means, afirst circular plate, a second circular plate spaced apart from saidfirst circular plate, resilient means joining the peripheries of saidfirst and said second circular plates, the area within said first plate,said second plate and said resilient means defining a chamber, means forsupporting said means defining a chamber within the severing means butpermitting the positioning of a body between the severing means and theresilient means, and means for developing an electrical discharge withinsaid chamber to produce a severing of a body at a predetermined point bycausing the portion of a body juxtaposed the severing means to beadvanced toward the severing means.

9. Cylindrical body forming means comprising annular severing means, afirst circular plate, a second circular plate spaced apart from saidfirst circular plate, cylindrical resilient means joining theperipheries of said first and said second circular plates, the areawithin said first circular plate, said second circular plate and saidresilient means forming a chamber for confining a fluid, means forsupporting said fluid chamber within the severing means but permittingthe positioning of a body between the severing means and the fluidchamber, and means for developing an electrical discharge within saidchamber to cause the severing of a body at a predetermined point bycausing the portion of a body juxtaposed the severing means to beadvanced toward the severing means.

10. The combination as defined in claim 9 comprising flanging radiusesformed adjacent to said annular severing means for flanging said severedcylindrical body at substantially the same time as the severingoperation.

1. Tubular body forming means comprising an annular die having acircular portion removed about its inner periphery, flanging radiusesformed at the junction of the removed portion and the inner surface ofsaid die, a severing knife positioned within the removed portion of saiddie, means defining a chamber within the die but permitting thepositioning of a body between the severing knife and the chamber means,and means for developing an electrical discharge within said chamber toproduce severing and flanging of a body at a predetermined point bycausing the portion of a body juxtaposed the severing knife to beadvanced toward the severing knife and against the flanging radius. 2.Tubular body forming means comprising annular severing means, a firstsealing plate, a second sealing plate spaced apart from and supported bysaid first sealing plate, the area between said first and said secondsealing plates defining a chamber, means for supporting said sealingplates within the severing means but permitting the positioning of abody between the severing means and the chamber defined by said sealingplates, and means for developing an electrical disCharge within saidchamber to produce a severing of a body at a predetermined point bycausing the portion of a body juxtaposed the severing means to beadvanced toward the severing means.
 3. The combination as defined inclaim 2 including resilient means positioned upon each of said sealingplates to effect a seal between its respective sealing plate and a bodyto be formed.
 4. The combination as defined in claim 3 wherein saidresilient means are O-rings of low frictional material.
 5. A cylindricalbody forming means comprising an expandable annular die, a groove formedabout the inside of said die, flanging radiuses formed at the junctionof the groove and the inside of said die, severing means positionedwithin said groove and directed inwardly, a first circular plate member,a second circular plate member positioned apart from and supported bysaid first plate member, the area between said first and said secondplate members defining a chamber having a gaseous atmosphere, a hornextension for supporting the circular plate members within the die butpermitting the positioning of a body between the severing means and theplate members, resilient means positioned upon each of said platemembers to effect a seal of the chamber to the body to be formed, and apair of electrodes positioned within the chamber and between said firstand said second plate members for developing an electrical dischargewithin said chamber and causing an expansion of the gaseous atmosphereto produce severing and flanging of a body at a predetermined point ofthe body by driving the portion of a body juxtaposed the severing meansand flanging radius to be advanced toward the severing means and theflanging radius.
 6. Cylindrical body forming means comprising anexpandable annular die, a severing knife positioned within said die anddirected inwardly, a horn extension, a pair of circular plates supportedby said horn extension and defining a chamber within the die butpermitting the positioning of a body between the severing knife and thecircular plates, inflatable means positioned about the periphery of eachof said circular means to effect a seal between its respective circularmeans and the body to be formed, and means for developing an electricaldischarge within said chamber between said circular plates to produce asevering of a body at a predetermined point by causing the portion of abody juxtaposed the severing knife to be advanced toward the severingknife.
 7. The combination as defined in claim 6 including a passagewaycommunicating with each of said resilient means positioned upon saidcircular plates for expanding said resilient means.
 8. Cylindrical bodyforming means comprising annular severing means, a first circular plate,a second circular plate spaced apart from said first circular plate,resilient means joining the peripheries of said first and said secondcircular plates, the area within said first plate, said second plate andsaid resilient means defining a chamber, means for supporting said meansdefining a chamber within the severing means but permitting thepositioning of a body between the severing means and the resilientmeans, and means for developing an electrical discharge within saidchamber to produce a severing of a body at a predetermined point bycausing the portion of a body juxtaposed the severing means to beadvanced toward the severing means.
 9. Cylindrical body forming meanscomprising annular severing means, a first circular plate, a secondcircular plate spaced apart from said first circular plate, cylindricalresilient means joining the peripheries of said first and said secondcircular plates, the area within said first circular plate, said secondcircular plate and said resilient means forming a chamber for confininga fluid, means for supporting said fluid chamber within the severingmeans but permitting the positioning of a body between the severingmeans and the fluid chamber, and means for developing an electricaldischarge within saId chamber to cause the severing of a body at apredetermined point by causing the portion of a body juxtaposed thesevering means to be advanced toward the severing means.
 10. Thecombination as defined in claim 9 comprising flanging radiuses formedadjacent to said annular severing means for flanging said severedcylindrical body at substantially the same time as the severingoperation.